Need advice..

I feel done and defeated. My fiance helps with nothing. I begged and begged the other day during an argument. Tested him yestersay. Our dog pooped a little bit on the floor in a back room of the house that my fiance is in a lot. He let it sit. All day. He cant even pick up a piece of dog shit on the carpet. I'm on my hands and knees every day cleaning up piss and shit from HIS DOG. And he wont even do some dishes or tidy the house. I just hurt and I'm tired and I dont wanna be here anymore... I am 13 weeks pregnant with twins, and I have a 2 year old, and I'm exhausted. I need help. I've begged and cried and he just doesnt seem to care... It makes me very scared about what's going to happen once these babies are born...